CVE-2026-53114
Description
In the Linux kernel, the following vulnerability has been resolved:
perf/amd/ibs: Avoid calling perf_allow_kernel() from the IBS NMI handler
Calling perf_allow_kernel() from the NMI context is unsafe and could be
fatal. Capture the permission at event-initialization time by storing it
in event->hw.flags, and have the NMI handler rely on that cached flag
instead of making the call directly.
Summary dbcve.org
The AMD IBS (Instruction Based Sampling) perf subsystem in the Linux kernel incorrectly calls perf_allow_kernel() from within the NMI handler context. NMI handlers run with interrupts disabled in atomic context, making function calls that may acquire locks or sleep unsafe and potentially fatal. The vulnerability is resolved by caching the permission check result during event initialization in event->hw.flags, allowing the NMI handler to safely read the pre-computed flag.
Mitigation
Update the Linux kernel to the version containing the fix that caches permission checks at event initialization rather than calling perf_allow_kernel() from NMI context. For systems unable to update immediately, avoid enabling perf IBS events in kernel mode as a workaround.